Extrachromosomal HIV-1 DNA in persistently infected U937 cells.

Persistent human immunodeficiency virus type 1 (HIV-1) infection of U937 monocytic cells resulted in the accumulation of novel forms of extrachromosomal viral DNA. These DNA species are larger than the genome size of HIV-1 and persist indefinitely. The extrachromosomal viral DNA species (E-DNA) were shown to be structurally stable by subcloning of infected cell lines and restriction fragment analysis. Similar E-DNA structures were observed in independent infections. Persistently infected monocytic cells had low levels of viral antigens, reflecting the low levels of viral RNA that were detected. These results support a role for E-DNA in persistent HIV-1 infection of monocytic cells.